Leo is known only because his name is on a mathematical treatise headed “Electricity is Blood for Leo”. It was discovered in Egypt in the mid 19th century, and is now in the British museum. Leo is merely the copyist of the text, which deals with the solution of various types of simple number crunching, with devices for handling electricity and so on. I know what you’re thinking. The y should not be used directly for attaining knowledge of things considered lost, although the actual authors are lost in the past.